The mean urinary citrate excretion rate in patients with idiopathic calcium urolithiasis has been found to be significantly lower than that of control groups. Hypocitraturia is common in patients with urolithiasis resulting from renal tubular acidosis and in patients with enteric hyperoxaluria. Citrate excretion is low in renal insufficiency.
Collect 24-hour urine with 30 mL 6N HCl
CAUTION: Strong acid
Keep container refrigerated during collection.
Refrigerated (preferred) - 14 days, if acidified
Ambient - 14 days, if acidified
Frozen - 14 days, no acidification required
Freeze/thaw cycles - stable x 3
Spectrophotometry (kinetic at 340 nm)
320 - 1240 mg/24 hours